System and method for imaging of moving subjects

ABSTRACT

The present disclosure provides a method for imaging of moving subjects. The method may include determining a motion range of a region of interest (ROI) of a subject in an axial direction. The method may also include causing a radiation source to emit, at each of a plurality of axial positions relative to the subject, radiation beams to the ROI to generate an image frame of the ROI. The radiation beams corresponding to the plurality of axial positions may jointly cover the motion range of the ROI in the axial direction. The method may further include determining a position of the ROI in the axial direction based on the image frames of the ROI, and determining, based on the positions of the ROI in the axial directions, at least one time bin in which therapeutic beams are to be emitted to the ROI.

TECHNICAL FIELD

The present disclosure generally relates to systems and methods forimaging, and more particularly, to systems and methods for imaging ofmoving subjects.

BACKGROUND

Imaging technologies, such as the CT imaging, have been widely used inthe medical field. In applications such as radiation therapy (RT)involving a moving subject, imaging may be used before treatment todetermine the motion range of the treatment target and/or organs at risk(OARs) of radiation damage. Often, a treatment is planned so thattherapeutic beams are applied during only a portion of a motion cycle,such as at 80% to 100% of full exhalation in a breathing cycle. It is ofgreat importance that the portion of the motion cycle that correspondsto the motion state in which the treatment target is in the plannedposition are set before treatment ensues on a particular day. Therefore,it is desired to develop methods and systems for imaging of the movingsubject in a better way such that the full range of motion is capturedin the images.

SUMMARY

According to an aspect of the present disclosure, a method is provided.The method may be implemented on a computing device having at least onestorage device storing a set of instructions, and at least one processorin communication with the at least one storage device. The method mayinclude determining a motion range of a region of interest (ROI) of asubject in an axial direction. The ROI may move due to a physiologicalmotion of the subject. The method may further include dividing thephysiological motion into a plurality of time bins. The method mayfurther include, in at least one of the plurality of time bins,determining a plurality of axial positions relative to the subject for aradiation source, and causing the radiation source to emit, at each ofthe plurality of axial positions relative to the subject, radiationbeams to the ROI to generate an image frame of the ROI. The radiationbeams corresponding to the plurality of axial positions may jointlycover the motion range of the ROI in the axial direction. The method mayfurther include determining, for each of the plurality of time bins, aposition of the ROI in the axial direction based on the image frames ofthe ROI generated in the corresponding time bin. And the method may alsoinclude determining, based on the positions of the ROI in the axialdirections and among the plurality of time bins, at least one time binin which therapeutic beams are to be emitted to the ROI.

In some embodiments, the determining a motion range of an ROI of asubject in an axial direction may include obtaining an image of thesubject based on a scan of the subject, identifying the ROI in the imageof the subject, and determining the motion range of the ROI based on theidentified ROI.

In some embodiments, the physiological motion of the subject may includeat least one of a respiration motion or a cardiac motion of the subject.

In some embodiments, the radiation source may generate X-rays with atleast two different energy spectra.

In some embodiments, the dividing the physiological motion into aplurality of time bins may include obtaining a time-varying motionsignal representing the physiological motion via a sensor coupled to thesubject, and dividing the time-varying motion signal into a plurality ofsegments, each of the plurality of the segments corresponding to one ofthe plurality of time bins.

In some embodiments, the determining, for a radiation source, aplurality of axial positions relative to the subject may includedetermining an axial coverage of the radiation beams of the radiationsource, and determining the plurality of axial positions for theradiation source such that the motion range of the ROI in the axialdirection is within a combination of the axial coverages of theradiation source at the plurality of axial positions relative to thesubject.

In some embodiments, the subject is supported by a table that may bemovable in the axial direction. The causing the radiation source toemit, at each of the plurality of axial positions relative to thesubject, radiation beams to the ROI to generate an image frame of theROI may include causing the table to move to a table location such thatthe radiation source is at one of the plurality of axial positionsrelative to the subject, and causing the radiation source to emit theradiation beams to the ROI while the table is at the table location.

In some embodiments, the radiation source may be installed on a gantrythat is movable in the axial direction. The causing the radiation sourceto emit, at each of the plurality of axial positions relative to thesubject, radiation beams to the ROI to generate an image frame of theROI may include causing the gantry to move to a gantry location suchthat the radiation source is at one of the plurality of axial positionsrelative to the subject, and causing the radiation source to emit theradiation beams to the ROI while the gantry is at the gantry location.

In some embodiments, the determining, based on the positions of the ROIin the axial directions and among the plurality of time bins, at leastone time bin, in which therapeutic beams are to be emitted to the ROImay include obtaining a planned position of the ROI at which thetherapeutic beams are to be emitted, determining, among the positions ofthe ROI in the axial direction, at least one position of the ROI thatmatches the planned position of the ROI at which the therapeutic beamsare to be emitted, and determining the at least one time bin based onthe at least one matched position of the ROI.

In some embodiments, the method may further include tracking a motion ofthe ROI. The determining, for a radiation source, a plurality of axialpositions relative to the subject may include determining the pluralityof axial positions relative to the subject based on the tracked motionof the ROI.

In some embodiments, the causing the radiation source to emit, at eachof the plurality of axial positions relative to the subject, radiationbeams to the ROI to generate an image frame of the ROI may includecausing the radiation source to emit, at each of the plurality of axialpositions relative to the subject, radiation beams to the ROI from oneor more angles at which the therapeutic beams are to be emitted to theROI.

According to an aspect of the present disclosure, a system is provided.The system may include at least one storage medium including a set ofinstructions and at least one processor in communication with the atleast one storage medium. When executing the instructions, the at leastone processor may configured to direct the system to perform operations.The operations may include determining a motion range of a region ofinterest (ROI) of a subject in an axial direction. The ROI may move dueto a physiological motion of the subject. The operations may furtherinclude dividing the physiological motion into a plurality of time bins.The operations may further include, in at least one of the plurality oftime bins, determining a plurality of axial positions relative to thesubject for a radiation source, and causing the radiation source toemit, at each of the plurality of axial positions relative to thesubject, radiation beams to the ROI to generate an image frame of theROI. The radiation beams corresponding to the plurality of axialpositions may jointly cover the motion range of the ROI in the axialdirection. The operations may further include determining, for each ofthe plurality of time bins, a position of the ROI in the axial directionbased on the image frames of the ROI generated in the corresponding timebin. And the operations may also include determining, based on thepositions of the ROI in the axial directions and among the plurality oftime bins, at least one time bin in which therapeutic beams are to beemitted to the ROI.

Additional features will be set forth in part in the description whichfollows, and in part will become apparent to those skilled in the artupon examination of the following and the accompanying drawings or maybe learned by production or operation of the examples. The features ofthe present disclosure may be realized and attained by practice or useof various aspects of the methodologies, instrumentalities andcombinations set forth in the detailed examples discussed below.

BRIEF DESCRIPTION OF THE DRAWINGS

The present disclosure is further described in terms of exemplaryembodiments. These exemplary embodiments are described in detail withreference to the drawings. These embodiments are non-limiting exemplaryembodiments, in which like reference numerals represent similarstructures throughout the several views of the drawings, and wherein:

FIG. 1 is a schematic diagram illustrating an exemplary imaging systemaccording to some embodiments of the present disclosure;

FIG. 2 is a schematic diagram illustrating an exemplary computing deviceon which at least a portion of the imaging system 100 can beimplemented, according to some embodiments of the present disclosure;

FIG. 3 is a schematic diagram illustrating hardware and/or softwarecomponents of an exemplary mobile device according to some embodimentsof the present disclosure;

FIG. 4 is a block diagram illustrating an exemplary processing deviceaccording to some embodiments of the present disclosure;

FIG. 5 is a flowchart illustrating an exemplary process for determiningat least one time bin in which therapeutic beams are to be emitted to aregion of interest (ROI) according to some embodiments of the presentdisclosure;

FIG. 6 is a flowchart illustrating an exemplary process for determininga motion range of the ROI according to some embodiments of the presentdisclosure;

FIG. 7 is a flowchart illustrating an exemplary process for dividing atime-varying motion signal according to some embodiments of the presentdisclosure;

FIG. 8 is a flowchart illustrating an exemplary process for determininga plurality of axial positions for a radiation source according to someembodiments of the present disclosure;

FIG. 9 is a flowchart illustrating an exemplary process for causing theradiation source to emit radiation beams according to some embodimentsof the present disclosure;

FIG. 10 is a flowchart illustrating another exemplary process forcausing the radiation source to emit radiation beams according to someembodiments of the present disclosure; and

FIG. 11 is a flowchart illustrating an exemplary process for determiningat least one time bin according to some embodiments of the presentdisclosure.

DETAILED DESCRIPTION

In the following detailed description, numerous specific details are setforth by way of examples in order to provide a thorough understanding ofthe relevant disclosure. However, it should be apparent to those skilledin the art that the present disclosure may be practiced without suchdetails. In other instances, well known methods, procedures, systems,components, and/or circuitry have been described at a relativelyhigh-level, without detail, in order to avoid unnecessarily obscuringaspects of the present disclosure. Various modifications to thedisclosed embodiments will be readily apparent to those skilled in theart, and the general principles defined herein may be applied to otherembodiments and applications without departing from the spirit and scopeof the present disclosure. Thus, the present disclosure is not limitedto the embodiments shown, but to be accorded the widest scope consistentwith the claims.

It will be understood that the term “system,” “engine,” “unit,”“module,” and/or “block” used herein are one method to distinguishdifferent components, elements, parts, section or assembly of differentlevel in ascending order. However, the terms may be displaced by anotherexpression if they may achieve the same purpose.

Generally, the word “module,” “unit,” or “block,” as used herein, refersto logic embodied in hardware or firmware, or to a collection ofsoftware instructions. A module, a unit, or a block described herein maybe implemented as software and/or hardware and may be stored in any typeof non-transitory computer-readable medium or another storage device. Insome embodiments, a software module/unit/block may be compiled andlinked into an executable program. It will be appreciated that softwaremodules can be callable from other modules/units/blocks or fromthemselves, and/or may be invoked in response to detected events orinterrupts. Software modules/units/blocks configured for execution oncomputing devices (e.g., processor 210 as illustrated in FIG. 2) may beprovided on a computer readable medium, such as a compact disc, adigital video disc, a flash drive, a magnetic disc, or any othertangible medium, or as a digital download (and can be originally storedin a compressed or installable format that needs installation,decompression, or decryption prior to execution). Such software code maybe stored, partially or fully, on a storage device of the executingcomputing device, for execution by the computing device. Softwareinstructions may be embedded in firmware, such as an erasableprogrammable read-only memory (EPROM). It will be further appreciatedthat hardware modules/units/blocks may be included of connected logiccomponents, such as gates and flip-flops, and/or can be included ofprogrammable units, such as programmable gate arrays or processors. Themodules/units/blocks or computing device functionality described hereinmay be implemented as software modules/units/blocks, but may berepresented in hardware or firmware. In general, themodules/units/blocks described herein refer to logicalmodules/units/blocks that may be combined with othermodules/units/blocks or divided into sub-modules/sub-units/sub-blocksdespite their physical organization or storage.

It will be understood that when a unit, engine, module or block isreferred to as being “on,” “connected to,” or “coupled to” another unit,engine, module, or block, it may be directly on, connected or coupledto, or communicate with the other unit, engine, module, or block, or anintervening unit, engine, module, or block may be present, unless thecontext clearly indicates otherwise. As used herein, the term “and/or”includes any and all combinations of one or more of the associatedlisted items.

The terminology used herein is for the purposes of describing particularexamples and embodiments only, and is not intended to be limiting. Asused herein, the singular forms “a,” “an,” and “the” may be intended toinclude the plural forms as well, unless the context clearly indicatesotherwise. It will be further understood that the terms “include” and/or“comprise,” when as used herein, specify the presence of integers,devices, behaviors, stated features, steps, elements, operations, and/orcomponents, but do not exclude the presence or addition of one or moreother integers, devices, behaviors, features, steps, elements,operations, components, and/or groups thereof.

Provided herein are systems and methods for imaging, such as for diseasediagnosis, physical check-up, or disease treatment. For example, theimaging systems and methods provided in the present disclosure may beused in an internal inspection (e.g., a non-invasive internalinspection) including, for the anatomical structure of one or moretissues or one or more organs, the metabolism of one or more tissues orone or more organs, the function of one or more tissues or one or moreorgans. The imaging system may find its applications in different fieldsother than the medical fields. For example, the imaging system may beused in an internal inspection (e.g., a non-invasive internalinspection) of one or more components. For example, the imaging systemsand methods provided in the present disclosure may be used in flawdetection of a component of a machine, bag or luggage security scanning,failure analysis, metrology, assembly analysis, void detection, wallthickness assessment, or the like, or any combination thereof.

Some embodiments of the present disclosure provide systems and methodsfor imaging of a moving ROI in a subject. In some embodiments, themoving ROI may move due to a physiological motion of the subject. Themethods may include determining a motion range of the moving ROI in anaxial direction. The method may further include dividing thephysiological motion of the subject into a plurality of time bins. In atleast one of the plurality of time bins, a radiation source may emit, ata plurality of axial positions relative to the subject, radiation beamsto the ROI to generate image frames of the ROI. On this occasion, theradiation beams emitted from the radiation source at the plurality ofaxial positions may jointly cover the axial range of the ROI whereverthe ROI moves. To this end, in some embodiments, the methods may includecausing the radiation source to exhaustively scan the ROI such that themotion range of the moving ROI in the axial direction are always coveredby the radiation beams in each time bin. In some alternativeembodiments, the methods may include causing the radiation source toactively track the axial range of the ROI in real time and cover thetracked axial range of the ROI by the radiation beams in each time bin.Then, the method may include determining, for each of the plurality oftime bins, a position of the ROI in the axial direction based on theimage frames of the ROI generated in the corresponding time bin. Themethod may further include determining, based on the positions of theROI in the axial direction and among the plurality of time bins, atleast one time bin in which therapeutic beams are to be emitted to theROI.

The following description is provided to facilitate better understandingof methods and/or systems for imaging of moving ROIs. The term “image”used in this disclosure may refer to a 2D image, a 3D image, a 4D image,and/or any related image data (e.g., projection data and/orcorresponding image data). The image data may correspond to adistribution of the degree of absorption of radiation beams by differentanatomical structures of the subject (e.g., a patient). The projectiondata corresponding to the image data may refer to a sum or line integralof linear attenuation coefficient(s) along a plurality of radiation beamdirections.

The following descriptions in connection with a CT imaging system areprovided for illustration purposes. It is understood that this is notintended to limit the scope of the present disclosure. For personshaving ordinary skills in the art, a certain amount of variations,changes and/or modifications may be deducted under the guidance of thepresent disclosure. Those variations, changes and/or modifications donot depart from the scope of the present disclosure.

FIG. 1 is a schematic diagram illustrating an exemplary imaging system100 according to some embodiments of the present disclosure. The imagingsystem 100 may include an imaging device 110, a network 120, one or moreterminals 130, a processing device 140, and a storage device 150.

The imaging device 110 may be a computed tomography (CT) imaging device.The imaging device 110 may include a gantry 113, a detector 112, a table114, and a scanning source 115. The gantry 113 may support the detector112 and the scanning source 115. A subject may be placed on the table114 for scanning. The scanning source 115 may emit X-rays to thesubject. The detector 112 may detect attenuated X-rays. The attenuatedX-rays may further be processed and converted to image data for imagereconstruction. Merely by way of example with reference to the imagingsystem 100, the X-rays may be generated by the scanning source 115according to the bremsstrahlung principle. The detector 112 may includea semiconductor detector, a gas detector, or a scintillation detector,etc. In some embodiments, the detector 112 may include a plurality ofdetector units, and the plurality of detector units may be arranged inany suitable manner. For example, the plurality of detector units may bearranged on a plane, and the detector 112 may be a flat panel detector.As another example, the plurality of detector units may be arranged onan arc surface, and the detector 112 may be an arc-shaped detector.

In some embodiments, a treatment device (not shown in the figure) may beadded to the imaging system 100. The treatment device may include atreatment radiation source, a gantry, a collimator, or the like, or acombination thereof. The treatment radiation source may be a linearaccelerator (LINAC). The collimator may control the shape of theradioactive rays generated by the treatment radiation source. In someembodiments, the imaging device 110 and the treatment device may share asame gantry. For example, the treatment radiation source may be mountedon the gantry 113. A subject may be placed on the table 114 fortreatment and/or scan. Merely by way of example, the imaging system 100may be an RT-CT system. The imaging device 110 described herein may beapplied in subject positioning and/or verification in image-guidedradiation therapy (IGRT). The image for guiding therapeutic beams may begenerated based on the image data processed/converted from theattenuated X-rays detected by the detector 112 of the imaging device110.

The network 120 may include any suitable network that can facilitate theexchange of information and/or data for the imaging system 100. In someembodiments, one or more components of the imaging system 100 (e.g., theimaging device 110, the terminal(s) 130, the processing device 140, thestorage device 150, etc.) may exchange information and/or data with oneor more other components of the imaging system 100, or an externaldevice (e.g., an external storage device) via the network 120. Forexample, the processing device 140 may obtain projection data from theimaging device 110 via the network 120. As another example, theprocessing device 140 may obtain user instructions from the terminal(s)130 via the network 120. The network 120 may be and/or include a publicnetwork (e.g., the Internet), a private network (e.g., a local areanetwork (LAN), a wide area network (WAN))), a wired network (e.g., anEthernet network), a wireless network (e.g., an 702.11 network, a Wi-Finetwork), a cellular network (e.g., a Long Term Evolution (LTE)network), a frame relay network, a virtual private network (“VPN”), asatellite network, a telephone network, routers, hubs, switches, servercomputers, and/or any combination thereof. Merely by way of example, thenetwork 120 may include a cable network, a wireline network, afiber-optic network, a telecommunications network, an intranet, awireless local area network (WLAN), a metropolitan area network (MAN), apublic telephone switched network (PSTN), a Bluetooth™ network, aZigBee™ network, a near field communication (NFC) network, or the like,or any combination thereof. In some embodiments, the network 120 mayinclude one or more network access points. For example, the network 120may include wired and/or wireless network access points such as basestations and/or internet exchange points through which one or morecomponents of the imaging system 100 may be connected to the network 120to exchange data and/or information.

The terminal(s) 130 may include a mobile device 131, a tablet computer132, a laptop computer 133, or the like, or any combination thereof. Insome embodiments, the mobile device 131 may include a smart home device,a wearable device, a smart mobile device, a virtual reality device, anaugmented reality device, or the like, or any combination thereof.Merely by way of example, the terminal(s) 130 may include a mobiledevice as illustrated in FIG. 3. In some embodiments, the smart homedevice may include a smart lighting device, a control device of anintelligent electrical apparatus, a smart monitoring device, a smarttelevision, a smart video camera, an interphone, or the like, or anycombination thereof. In some embodiments, the wearable device mayinclude a bracelet, footwear, eyeglasses, a helmet, a watch, clothing, abackpack, a smart accessory, or the like, or any combination thereof. Insome embodiments, the mobile device may include a mobile phone, apersonal digital assistant (PDA), a gaming device, a navigation device,a point of sale (POS) device, a laptop, a tablet computer, a desktop, orthe like, or any combination thereof. In some embodiments, the virtualreality device and/or the augmented reality device may include a virtualreality helmet, virtual reality glasses, a virtual reality patch, anaugmented reality helmet, augmented reality glasses, an augmentedreality patch, or the like, or any combination thereof. For example, thevirtual reality device and/or the augmented reality device may include aGoogle Glass™, an Oculus Rift™, a Hololens™, a Gear VR™, etc. In someembodiments, the terminal(s) 130 may be part of the processing device140.

The processing device 140 may process data, images, and/or informationobtained from the imaging device 110, the terminal(s) 130, the storagedevice 150, an external device, etc. In some embodiments, the processingdevice 140 may be a single server or a server group. The server groupmay be centralized or distributed. In some embodiments, the processingdevice 140 may be local to or remote from other components of theimaging system 100 (e.g., the imaging device 110). For example, theprocessing device 140 may access, via the network 120, data, images,and/or information stored in the imaging device 110, the terminal(s)130, the storage device 150, an external device, etc. As anotherexample, the processing device 140 may be directly connected to theimaging device 110, the terminal(s) 130, and/or the storage device 150to access stored data, images, and/or information. In some embodiments,the processing device 140 may be implemented on a cloud platform. Merelyby way of example, the cloud platform may include a private cloud, apublic cloud, a hybrid cloud, a community cloud, a distributed cloud, aninter-cloud, a multi-cloud, or the like, or any combination thereof. Insome embodiments, the processing device 140 may be implemented by acomputing device 200 having one or more components as illustrated inFIG. 2.

The storage device 150 may store data, instructions, and/or any otherinformation. In some embodiments, the storage device 150 may store dataobtained from the terminal(s) 130 and/or the processing device 140. Insome embodiments, the storage device 150 may store data and/orinstructions that the processing device 140 may execute or use toperform exemplary methods described in the present disclosure. In someembodiments, the storage device 150 may include a mass storage,removable storage, a volatile read-and-write memory, a read-only memory(ROM), or the like, or any combination thereof. Exemplary mass storagemay include a magnetic disk, an optical disk, a solid-state drive, etc.Exemplary removable storage may include a flash drive, a floppy disk, anoptical disk, a memory card, a zip disk, a magnetic tape, etc. Exemplaryvolatile read-and-write memories may include a random access memory(RAM). Exemplary RAM may include a dynamic RAM (DRAM), a double daterate synchronous dynamic RAM (DDR SDRAM), a static RAM (SRAM), athyristor RAM (T-RAM), and a zero-capacitor RAM (Z-RAM), etc. ExemplaryROM may include a mask ROM (MROM), a programmable ROM (PROM), anerasable programmable ROM (EPROM), an electrically erasable programmableROM (EEPROM), a compact disk ROM (CD-ROM), and a digital versatile diskROM, etc. In some embodiments, the storage device 150 may be implementedon a cloud platform. Merely by way of example, the cloud platform mayinclude a private cloud, a public cloud, a hybrid cloud, a communitycloud, a distributed cloud, an inter-cloud, a multi-cloud, or the like,or any combination thereof.

In some embodiments, the storage device 150 may be connected to thenetwork 120 to communicate with one or more other components of theimaging system 100 (e.g., the processing device 140, the terminal(s)130). One or more components of the imaging system 100 may access thedata or instructions stored in the storage device 150 via the network120. In some embodiments, the storage device 150 may be directlyconnected to or communicate with one or more other components of theimaging system 100 (e.g., the processing device 140, the terminal(s)130). In some embodiments, the storage device 150 may be part of theprocessing device 140.

FIG. 2 is a schematic diagram illustrating an exemplary computing device200 on which at least a portion of the imaging system 100 can beimplemented, according to some embodiments of the present disclosure. Asillustrated in FIG. 2, the computing device 200 may include a processor210, storage 220, an input/output (I/O) 230, and a communication port240.

The processor 210 may execute computer instructions (e.g., program code)and perform functions of the processing device 140 in accordance withtechniques described herein. The computer instructions may include, forexample, routines, programs, objects, components, data structures,procedures, modules, and functions, which perform particular functionsdescribed herein. For example, the processor 210 may process motion dataobtained from the imaging device 110, the terminal(s) 130, the storagedevice 150, and/or any other component of the imaging system 100. Asanother example, the processor 210 may process image(s) obtained fromthe terminal(s) 130, the storage device 150, and/or any other componentof the imaging system 100. In some embodiments, the processor 210 mayinclude one or more hardware processors, such as a microcontroller, amicroprocessor, a reduced instruction set computer (RISC), anapplication specific integrated circuits (ASICs), anapplication-specific instruction-set processor (ASIP), a centralprocessing unit (CPU), a graphics processing unit (GPU), a physicsprocessing unit (PPU), a microcontroller unit, a digital signalprocessor (DSP), a field programmable gate array (FPGA), an advancedRISC machine (ARM), a programmable logic device (PLD), any circuit orprocessor capable of executing one or more functions, or the like, or acombinations thereof.

Merely for illustration, only one processor is described in thecomputing device 200. However, it should be noted that the computingdevice 200 in the present disclosure may also include multipleprocessors. Thus, operations and/or method steps that are performed byone processor as described in the present disclosure may also be jointlyor separately performed by the multiple processors. For example, if inthe present disclosure the processor of the computing device 200executes both operation A and operation B, it should be understood thatoperation A and operation B may also be performed by two or moredifferent processors jointly or separately in the computing device 200(e.g., a first processor executes operation A and a second processorexecutes operation B, or the first and second processors jointly executeoperations A and B).

The storage 220 may store data/information obtained from the imagingdevice 110, the terminal(s) 130, the storage device 150, and/or anyother component of the imaging system 100, an external device, etc. Insome embodiments, the storage 220 may include a mass storage, removablestorage, a volatile read-and-write memory, a read-only memory (ROM), orthe like, or a combination thereof. For example, the mass storage mayinclude a magnetic disk, an optical disk, a solid-state drive, etc. Theremovable storage may include a flash drive, a floppy disk, an opticaldisk, a memory card, a zip disk, a magnetic tape, etc. The volatileread-and-write memory may include a random access memory (RAM). The RAMmay include a dynamic RAM (DRAM), a double date rate synchronous dynamicRAM (DDR SDRAM), a static RAM (SRAM), a thyristor RAM (T-RAM), and azero-capacitor RAM (Z-RAM), etc. The ROM may include a mask ROM (MROM),a programmable ROM (PROM), an erasable programmable ROM (EPROM), anelectrically erasable programmable ROM (EEPROM), a compact disk ROM(CD-ROM), and a digital versatile disk ROM, etc. In some embodiments,the storage 220 may store one or more programs and/or instructions toperform exemplary methods described in the present disclosure. Forexample, the storage 220 may store a program for the processing device140 for imaging and/or determining at least one time bin in whichtherapeutic beams are to be emitted to the ROI.

The I/O 230 may input and/or output signals, data, information, etc. Insome embodiments, the I/O 230 may enable user interaction with theprocessing device 140. In some embodiments, the I/O 230 may include aninput device and an output device. Examples of the input device mayinclude a keyboard, a mouse, a touch screen, a microphone, or the like,or a combination thereof. Examples of the output device may include adisplay device, a loudspeaker, a printer, a projector, or the like, or acombination thereof. Examples of the display device may include a liquidcrystal display (LCD), a light-emitting diode (LED)-based display, aflat panel display, a curved screen, a television device, a cathode raytube (CRT), a touch screen, or the like, or a combination thereof.

The communication port 240 may be connected to a network (e.g., thenetwork 120) to facilitate data communications. The communication port240 may establish connections between the processing device 140 and theimaging device 110, the terminal(s) 130, and/or the storage device 150.The connection may be a wired connection, a wireless connection, anyother communication connection that can enable data transmission and/orreception, and/or a combination of these connections. The wiredconnection may include, for example, an electrical cable, an opticalcable, a telephone wire, or the like, or a combination thereof. Thewireless connection may include, for example, a Bluetooth™ link, aWi-Fi™ link, a WiMax™ link, a WLAN link, a ZigBee link, a mobile networklink (e.g., 3G, 4G, 5G, etc.), or the like, or a combination thereof. Insome embodiments, the communication port 240 may be and/or include astandardized communication port, such as RS232, RS485, etc. In someembodiments, the communication port 240 may be a specially designedcommunication port. For example, the communication port 240 may bedesigned in accordance with the digital imaging and communications inmedicine (DICOM) protocol.

FIG. 3 is a schematic diagram illustrating exemplary hardware and/orsoftware components of an exemplary mobile device 300 on which theterminal(s) 130 may be implemented according to some embodiments of thepresent disclosure. As illustrated in FIG. 3, the mobile device 300 mayinclude a communication platform 310, a display 320, a graphicprocessing unit (GPU) 330, a central processing unit (CPU) 340, an I/O350, a memory 360, and storage 390. In some embodiments, any othersuitable component, including but not limited to a system bus or acontroller (not shown), may also be included in the mobile device 300.In some embodiments, a mobile operating system 370 (e.g., iOS™,Android™, Windows Phone™) and one or more applications 380 may be loadedinto the memory 360 from the storage 390 in order to be executed by theCPU 340. The applications 380 may include a browser or any othersuitable mobile apps for receiving and rendering information relating toimage processing or other information from the processing device 140.User interactions with the information stream may be achieved via theI/O 350 and provided to the processing device 140 and/or othercomponents of the imaging system 100 via the network 120.

To implement various modules, units, and their functionalities describedin the present disclosure, computer hardware platforms may be used asthe hardware platform(s) for one or more of the elements describedherein. A computer with user interface elements may be used to implementa personal computer (PC) or any other type of work station or terminaldevice. A computer may also act as a server if appropriately programmed.

FIG. 4 is a block diagram illustrating an exemplary processing device140 according to some embodiments of the present disclosure. Theprocessing device 140 may include a motion range determination module410, a physiological motion dividing module 420, an axial positiondetermination module 430, a radiation beam emitting module 440, a ROIposition determination module 450, and a time bin determination module460.

The processing device 140 may be implemented on various components(e.g., the computing device 200 as illustrated in FIG. 2, the mobiledevice 300 as illustrated in FIG. 3).

The motion range determination module 410 may be configured to determinea motion range of a region of interest (ROI) of a subject in an axialdirection. In some embodiments, the ROI may refer to a physical portionof the subject that is supposed to be illuminated and/or treated bytherapeutic beams in a therapeutic process. In some embodiments, the ROImay move due to a physiological motion of the subject. The motion rangeof the ROI in the axial direction may refer to the entire range ofmotion of the ROI in the axial direction during a full cycle of thephysiological motion. In some embodiments, the motion range of the ROIin the axial direction may be represented in a coordinate system. Insome embodiments, to determine the motion range of the ROI of thesubject in the axial direction, the motion range determination module410 may be configured to obtain an image of the subject based on a scanof the subject, identify the ROI in the image of the subject, anddetermine the motion range of the ROI based on the identified ROI.

The physiological motion dividing module 420 may be configured to dividethe physiological motion into a plurality of time bins. In someembodiments, each of the plurality of time bins may be short enough suchthat in the each of the plurality of time bins, the ROI of the subjectmay be considered to be static or approximately static. For each of theplurality of time bins, data obtained therein may be used to reconstructan image, which may be used to provide information of the ROI in thecorresponding time bin. In some embodiments, to divide the physiologicalmotion into a plurality of time bins, the physiological motion dividingmodule 420 may be configured to obtain a time-varying motion signalrepresenting the physiological motion via a sensor coupled to thesubject, and divide the time-varying motion signal into a plurality ofsegments.

The axial position determination module 430 may be configured todetermine a plurality of axial positions relative to the subject for aradiation source. In some embodiments, the radiation source may generateX-rays with at least two different energy spectra. In some embodiments,to determine the plurality of axial positions relative to the subject,the axial position determination module 430 may be configured todetermine an axial coverage of the radiation beams of the radiationsource, and determine the plurality of axial positions for the radiationsource such that the motion range of the ROI in the axial direction iswithin a combination of the axial coverages of the radiation source atthe plurality of axial positions relative to the subject. In someembodiments, to determine the plurality of axial positions relative tothe subject, the axial position determination module 430 may also beconfigured to track the motion of the ROI in real time, and determinethe plurality of axial positions relative to the subject based on thereal-time axial range of the ROI.

The radiation beam emitting module 440 may be configured to cause theradiation source to emit, at each of the plurality of axial positionsrelative to the subject, radiation beams to the ROI to generate an imageframe of the ROI. In some embodiments, the subject may be supported by atable that is movable in the axial direction. The radiation beamemitting module 440 may be configured to cause the table to move to atable location such that the radiation source is at one of the pluralityof axial positions relative to the subject, and cause the radiationsource to emit the radiation beams to the ROI while the table is at thetable location. In some embodiments, the radiation source may beinstalled on a gantry that is movable in the axial direction. Theradiation beam emitting module 440 may be configured to cause the gantryto move to a gantry location such that the radiation source is at one ofthe plurality of axial positions relative to the subject, and cause theradiation source to emit the radiation beams to the ROI while the gantryis at the gantry location. In some embodiments, the radiation beamemitting module 440 may be configured to cause the radiation source toemit, at each of the plurality of axial positions relative to thesubject, the radiation beams to the ROI from one or more angles at whichthe therapeutic beams are to be emitted to the ROI. In this way, amotion trajectory of the ROI may be most relevantly determined from apoint-of-view corresponding to the one or more angles of a plannedtherapeutic beam entry.

The ROI position determination module 450 may be configured todetermine, for each of the plurality of time bins, a position of the ROIbased on the image frames of the ROI generated in the corresponding timebin. In some embodiments, for each of the plurality of time bins, theROI position determination module 450 may be configured to identify theROI in each of the image frames of the ROI generated in thecorresponding time bin. Alternatively, the ROI position determinationmodule 450 may be configured to synthesize the plurality of image framesgenerated in a same time bin to obtain a synthesized image thatrepresents the whole ROI, and then identify the whole ROI in thesynthesized image. In some embodiments, the ROI position determinationmodule 450 may be further configured to determine a position of the ROIbased on the identified ROI in each of the image frames.

The time bin determination module 460 may be configured to determine,based on the positions of the ROI and among the plurality of time bins,at least one time bin in which therapeutic beams are to be emitted tothe ROI. In some embodiments, to determine the at least one time bin,the time bin determination module 460 may be configured to obtain aplanned position of the ROI at which the therapeutic beams are to beemitted, determine, among the positions of the ROI, at least oneposition of the ROI that matches the planned position of the ROI atwhich the therapeutic beams are to be emitted, and determine the atleast one time bin based on the at least one matched position of theROI.

It should be noted that the above descriptions of the processing device140 are provided for the purposes of illustration, and not intended tolimit the scope of the present disclosure. For persons having ordinaryskills in the art, various modifications and changes in the forms anddetails of the application of the above method and system may occurwithout departing from the principles of the present disclosure. Merelyby way of example, the processing device 140 may include one or moreother modules. However, those variations and modifications also fallwithin the scope of the present disclosure.

FIG. 5 is a flowchart illustrating an exemplary process 500 fordetermining at least one time bin in which therapeutic beams are to beemitted to the ROI according to some embodiments of the presentdisclosure. In some embodiments, at least part of the process 500 may beperformed by the processing device 140 (implemented in, for example, thecomputing device 200 shown in FIG. 2). For example, the process 500 maybe stored in a storage device (e.g., the storage device 150, the storage220, the storage 390) in the form of instructions (e.g., anapplication), and invoked and/or executed by the processing device 140(e.g., the processor 210 illustrated in FIG. 2, the CPU 340 illustratedin FIG. 3, or one or more modules in the processing device 140illustrated in FIG. 4). The operations of the illustrated processpresented below are intended to be illustrative. In some embodiments,the process 500 may be accomplished with one or more additionaloperations not described, and/or without one or more of the operationsdiscussed. Additionally, the order of the operations of the process 500as illustrated in FIG. 5 and described below is not intended to belimiting.

In 502, the processing device 140 (e.g., the motion range determinationmodule 410) may determine a motion range of a region of interest (ROI)of a subject in an axial direction.

In some embodiments, the subject may be biological or non-biological.Merely by way of example, the subject may include a patient, a man-madesubject, etc. As another example, the subject may include a specificportion, organ, and/or tissue of a patient. Specifically, the subjectmay include a head, a brain, a neck, a body, a shoulder, an arm, athorax, a heart, a stomach, a blood vessel, a soft tissue, a knee, afoot of a patient, or the like, or any combination thereof. In someembodiments, the region of interest (ROI) may refer to a physicalportion (e.g., a tissue, an organ, a portion of a tissue, a portion ofan organ, etc.) of the subject that is supposed to be illuminated and/ortreated by therapeutic beams in a therapeutic process. For illustrationpurpose, assuming that the subject is a patient, the ROI may be a tumorthat is on a specific organ of the patient and is to be illuminatedand/or treated by therapeutic beams.

In some embodiments, the ROI may move due to a physiological motion ofthe subject. Exemplary physiological motion of the subject may include arespiration motion or a cardiac motion of the subject. Merely by way ofexample, due to a cardiac motion, an ROI on the heart or an organ (e.g.,the left lung) near the heart may move with the beat of the heart. Asanother example, due to the respiration motion, an ROI on the lung maybe located in different positions at different phases of the respiratorystate (e.g., an exhalation state, an inhalation state).

The motion range of the ROI in the axial direction may refer to theentire range of motion of the ROI in the axial direction during a fullcycle of the physiological motion. The axial direction may refer to thedirection of the relative movement between the table 114 and thescanning source 115 during the scanning, which is identical to thedirection pointing from the head to the feet when a patient lies on thetable 114 for scanning. The motion range of the ROI may be determinedsuch that, at any time point in the full cycle of the physiologicalmotion, any part of the ROI is within the motion range of the ROI. Insome embodiments, the processing device 140 (e.g., the motion rangedetermination module 410) may determine a coordinate system forrepresenting the motion range of the ROI in the axial direction. Thecoordinate system may have any number of dimensions and the dimensionsmay be in any direction. Exemplary coordinate system may include a worldcoordinate system including three dimensions, an image coordinatesystem, or the like, or any combination thereof. The coordinate originof the coordinate system may be located at any suitable position. Forexample, the coordinate origin of the world coordinate system may belocated at the isocenter of the imaging device 110.

In some embodiments, the processing device 140 may determine the motionrange of the ROI in the axial direction via one or more imagesrepresenting the ROI. The one or more images representing the ROI may beobtained by performing a scan on the subject using the imaging device110 in at least one full cycle of the physiological motion. For example,the scanning source 115 may emit X-rays to scan the subject (e.g., thehead, a breast, etc., of a patient) located on the table 114. Thedetector 112 may detect one or more X-rays emitted from the scanningsource 115 or scattered by the subject to obtain projection values.Further, the processing device 140 may reconstruct the one or moreimages representing the ROI based on the projection values using areconstruction algorithm. Exemplary reconstruction algorithms mayinclude an iterative reconstruction algorithm (e.g., a statisticalreconstruction algorithm), a Fourier slice theorem algorithm, a fan-beamreconstruction algorithm, an analytic reconstruction algorithm, analgebraic reconstruction technique (ART), a simultaneous algebraicreconstruction technique (SART), a filtered back projection (FBP)technique, a Feldkamp-Davis-Kress (FDK) reconstruction technique, or thelike, or any combination thereof.

In some embodiments, the one or more images may include a 3D CT image, a4D CT image, cine images, or the like, or any combination thereof. Theprocessing device 140 (e.g., the motion range determination module 410)may identify the ROI in the one or more images and further determine themotion range of the ROI based on the identified ROI. For example, cineimaging (or 4D CT scanning) may be performed by the radiation sourceover at least one full cycle of the physiological motion, and the motionrange of the ROI can be identified from the cine images (or the 4D CTimage) accordingly. More descriptions regarding the determination of themotion range of the ROI may be found elsewhere in the presentdisclosure. See, e.g., FIG. 6 and the descriptions thereof.

In 504, the processing device 140 (e.g., the physiological motiondividing module 420) may divide the physiological motion into aplurality of time bins.

In some embodiments, each of the plurality of time bins may be shortenough such that in the each of the plurality of time bins, the ROI ofthe subject may be considered to be static or approximately static. Foreach of the plurality of time bins, data (e.g., projection values)obtained therein may be used to reconstruct an image, which may be usedto provide information of the ROI in the corresponding time bin.Exemplary information of the ROI may include a position of the ROI, aprofile of the ROI, a size of the ROI, or the like, or any combinationthereof. In a specific embodiment, a full cycle of a respiration motionmay typically last 2-6 seconds. The full cycle of the respiration motionmay be divided into, for example, 10 time bins, and thus each time binmay span 200-600 ms. In each time bin, the ROI of the subject may beconsidered to be static or approximately static, and therefore artifactsor blurs in the image reconstructed from data generated in that time binmay be eliminated.

In some embodiments, to divide the physiological motion into a pluralityof time bins, the processing device 140 (e.g., the physiological motiondividing module 420) may obtain a time-varying motion signalrepresenting the physiological motion via a sensor coupled to thesubject, and divide the time-varying motion signal into a plurality ofsegments. In some alternative embodiments, the processing device 140(e.g., the physiological motion dividing module 420) may extract amotion signal from cine images or a 4D CT image of the subject torepresent the physiological motion of the subject, and divide theextracted motion signal into a plurality of segments. Each of theplurality of the segments may correspond to one of the plurality of timebins. More descriptions regarding the dividing the physiological motionmay be found elsewhere in the present disclosure. See, e.g., FIG. 7 andthe descriptions thereof.

In some embodiments, the physiological motion may be divided into theplurality of time bins evenly or unevenly. For example, in one cycle ofthe respiration motion, the respiration motion may be divided evenlysuch that all time bins have an identical time span (e.g., 300 ms). Asanother example, in one cycle of the respiration motion, the respirationmotion may be divided unevenly such that a time bin corresponding to theexhalation state (e.g., at 80% to 100% of full exhalation) has a largertime span than a time bin corresponding to another breathing state(e.g., the inhalation state).

In 506, in at least one of the plurality of time bins, the processingdevice 140 (e.g., the axial position determination module 430) maydetermine, for a radiation source, a plurality of axial positionsrelative to the subject.

In some embodiments, the radiation source (e.g., the scanning source 115of the imaging device 110) may generate X-rays with at least twodifferent energy spectra. Specifically, the imaging device 110 mayinclude a multiple energy CT, a multiple spectral CT, or the like.Multiple energy imaging may be achieved using a multilayer detector. Themultiple energy CT may include a dual energy CT which uses fastswitching of two energy spectra. The multiple spectral CT may include aspectrally-sensitive CT. In some embodiments, the contrast in imagesobtained by performing a scan using the radiation source generatingX-rays with at least two different energy spectra may be improved. Forexample, overlying ribs in lung images obtained in the dual energy CTmay be removed (or distinguishable) from the lung images, which maybetter reveal an ROI (e.g., a tumor) in the lung region.

In some embodiments, an axial coverage of the radiation beams (alsoreferred to as the axial field of view (FOV)) emitted by the radiationsource is not wide enough to cover the axial range of the ROI. In suchcase, the processing device 140 may cause the radiation source toperform multiple scans at different axial positions relative to thesubject such that the axial range of the ROI may be completely includedin the joint axial coverage of the radiation beams. To this end, in someembodiments, the processing device 140 (e.g., the axial positiondetermination module 430) may determine the plurality of axial positionsfor the radiation source such that the entire motion range of the ROI inthe axial direction is within a combination of the axial coverages ofthe radiation source at the plurality of axial positions relative to thesubject. For brevity, the scanning of the radiation source in one timebin to completely cover the entire motion range of the ROI in the axialdirection may be referred to as “exhaustive scan”. In some alternativeembodiments, the processing device 140 (e.g., the axial positiondetermination module 430) may actively track the ROI and determine theplurality of axial positions for the radiation source such that thereal-time axial range of the ROI, which may be a portion of the entiremotion range, is within a combination of the axial coverages of theradiation source at the plurality of axial positions relative to thesubject. For brevity, the scanning of the radiation source in one timebin to actively track and cover the real-time axial range of the ROI maybe referred to as “predictive scan”.

In some embodiments, the plurality of axial positions of the radiationsource relative to the subject may vary in steps or continuously. Forexample, the plurality of axial positions relative to the subject maycontinuously change while the radiation source is emitting the radiationbeams during each time bin. As another example, the plurality of axialpositions relative to the subject may be discrete positions and theradiation source may emit the radiation beams only when it reaches thedesignated positions. More descriptions regarding the determination ofthe axial positions for the radiation source may be found elsewhere inthe present disclosure. See, e.g., FIG. 8 and the descriptions thereof.

In 508, the processing device 140 (e.g., the radiation beam emittingmodule 440) may cause the radiation source to emit, at each of theplurality of axial positions relative to the subject, radiation beams tothe ROI to generate an image frame of the ROI.

The radiation source (e.g., the scanning source 115) may include anX-ray tube which may generate X-rays with a power supply provided by avoltage generator. Specifically, the X-ray tube may at least include ananode and a cathode. The cathode may include one or more filaments(e.g., a tungsten wire, an iridium wire, a nickel wire, a molybdenumwire) configured to emit free electrons. The free electrons may beaccelerated in an electric field between the cathode and the anode toform an electron beam striking the anode to further generate radioactiverays such as X-rays. The anode may be made of an electrically conductivematerial, and may have a high mechanical strength under a hightemperature and have a high melting point. Exemplary materials mayinclude titanium zirconium molybdenum (TZM), ferrum, cuprum, tungsten,graphite, or the like, or an alloy thereof, or any combination thereof.In a dual energy CT system with a single radiation source (e.g., thescanning source 115), an X-ray tube included in the single radiationsource may generate X-rays with a power supply provided by a voltagegenerator. The power supply provided by the voltage generator mayrapidly switch between a low X-ray tube voltage and a high X-ray tubevoltage, and then X-rays with two different energy spectra may begenerated to perform a scan on the ROI.

In some embodiments, when the radiation source emits radiation beams tothe ROI at each of the plurality of axial positions relative to thesubject, the detector may detect one or more X-rays emitted from thescanning source or scattered by the ROI to obtain projection values. Theprojection values may be transmitted to the processing device 140 forgenerating an image frame. In some embodiments, the processing device140 may reconstruct an image frame based on the projection values usinga reconstruction algorithm. Exemplary reconstruction algorithms mayinclude an iterative reconstruction algorithm (e.g., a statisticalreconstruction algorithm), a Fourier slice theorem algorithm, a fan-beamreconstruction algorithm, an analytic reconstruction algorithm, analgebraic reconstruction technique (ART), a simultaneous algebraicreconstruction technique (SART), a filtered back projection (FBP)technique, a Feldkamp-Davis-Kress (FDK) reconstruction technique, or thelike, or any combination thereof.

In some embodiments, the radiation beams emitted by the radiation sourceat a specific axial position relative to the subject may cover a portionof the ROI in the axial direction. Correspondingly, an image framecorresponding to the radiation source at the specific axial position mayinclude the information of the portion of the ROI. The radiation beamsemitted by the radiation source at the plurality of axial positions mayjointly cover the motion range or the real-time axial range of the ROIin the axial direction. Correspondingly, the image frames correspondingto the radiation source at the plurality of axial positions relative tothe subject may jointly include the whole information of the ROI in theaxial direction.

In some embodiments, the subject may be supported by a table (e.g., thetable 114 of the imaging device 110) that is movable in the axialdirection. The processing device 140 (e.g., the radiation beam emittingmodule 440) may cause the table to move to a table location such thatthe radiation source is at one of the plurality of axial positionsrelative to the subject. And the processing device 140 (e.g., theradiation beam emitting module 440) may further cause the radiationsource to emit the radiation beams to the ROI while the table is at thetable location. In some alternative embodiments, the radiation sourcemay be installed on a gantry (e.g., the gantry 113 of the imaging device110) that is movable in the axial direction. The processing device 140(e.g., the radiation beam emitting module 440) may cause the gantry tomove to a gantry location such that the radiation source is at one ofthe plurality of axial positions relative to the subject. And theprocessing device 140 (e.g., the radiation beam emitting module 440) mayfurther cause the radiation source to emit the radiation beams to theROI while the gantry is at the gantry location.

In some embodiments, the processing device 140 may cause the radiationsource to emit, at each of the plurality of axial positions relative tothe subject, the radiation beams to the ROI from one or more angles atwhich the therapeutic beams are to be emitted to the ROI. Thetherapeutic beams may include X-ray beams, charged particle beams,neutron beams, ultrasound beams, or the like, or any combinationthereof, which may be used to deliver a treatment on the ROI. In someembodiments, the one or more angles may be obtained from a treatmentplan in which a planned therapeutic beam entry may be pre-determined. Asused herein, each of the one or more angles may correspond to a discreteangle value or an angular range. In this way, a motion trajectory of theROI may be most relevantly determined from a point-of-view correspondingto the one or more angles of the planned therapeutic beam entry(beam's-eye-view imaging).

In 510, the processing device 140 (e.g., the ROI position determinationmodule 450) may determine, for each of the plurality of time bins, aposition of the ROI based on the image frames of the ROI generated inthe corresponding time bin.

In some embodiments, as illustrated in operation 504, each of theplurality of time bins may be short enough such that in each time bin,the ROI of the subject may be considered to be static or approximatelystatic. For each of the plurality of time bins, the processing device140 (e.g., the ROI position determination module 450) may identify theROI in each of the image frames of the ROI generated in thecorresponding time bin. Alternatively, the processing device 140 (e.g.,the ROI position determination module 450) may synthesize the pluralityof image frames generated in a same time bin to obtain a synthesizedimage that represents the whole ROI, and then identify the whole ROI inthe synthesized image. Exemplary techniques for identifying the ROI ineach of the image frames or in the synthesized image may include animage segmentation technique, a manual annotation technique, a machinelearning technique, or the like, or any combination thereof.Furthermore, the processing device 140 (e.g., the ROI positiondetermination module 450) may determine a position of the ROI based onthe identified ROI in each of the image frames. In some embodiments, theposition of the ROI in the axial direction may include a position of theROI relative to other organs/tissues in the subject, a position of theROI relative to the radiation source that emits the therapeutic beams, aposition of the ROI relative to other components of the imaging device110 (e.g., the gantry 113), or the like, or a combination thereof. Theposition of the ROI may be represented using at least one set ofcoordinates. For example, the position of the ROI may be representedusing a world coordinate system or an image coordinate system.

In 512, the processing device 140 (e.g., the time bin determinationmodule 460) may determine, based on the positions of the ROI and amongthe plurality of time bins, at least one time bin in which therapeuticbeams are to be emitted to the ROI.

In some embodiments, the processing device 140 (e.g., the time bindetermination module 460) may determine the at least one time bin thatcorresponds to the ROI being in a planned position at which thetherapeutic beams are to be emitted. As such, the therapeutic beams maybe emitted to the ROI when the ROI moves to the planned position (e.g.,the position designated in a treatment plan) such that therapeutic beamsmay be accurately emitted to the ROI and the treatment may be accuratelydelivered to the ROI, which may reduce the dose of X-rays exposed toother parts of the subject (e.g., an organ at risk).

Specifically, the processing device 140 (e.g., the time bindetermination module 460) may obtain a planned position of the ROI atwhich the therapeutic beams are to be emitted. Then the processingdevice 140 (e.g., the time bin determination module 460) may determine,among the positions of the ROI, at least one position of the ROI thatmatches the planned position of the ROI at which the therapeutic beamsare to be emitted. Furthermore, the processing device 140 (e.g., thetime bin determination module 460) may determine the at least one timebin based on the at least one matched position of the ROI. Moredescriptions regarding the determination of the at least one time binmay be found elsewhere in the present disclosure. See, e.g., FIG. 11 andthe descriptions thereof.

It should be noted that the above descriptions of the process 500 areprovided for the purposes of illustration, and not intended to limit thescope of the present disclosure. For persons having ordinary skills inthe art, various modifications and changes in the forms and details ofthe application of the above method and system may occur withoutdeparting from the principles of the present disclosure. In someembodiments, the process 500 may include one or more other operations.However, those variations and modifications also fall within the scopeof the present disclosure. For example, as illustrated in the operation502, the motion range of the ROI of the subject in the axial directionmay be determined. Persons having ordinary skills in the art mayunderstand that, the motion range of the ROI may also be represented in2D (e.g., in the axial direction and a lateral direction) and/or 3D (inthe axial direction, a lateral direction and a vertical direction). Forexample, the processing device 140 may determine the motion range of theROI in the lateral direction and/or the vertical direction. Then, theprocessing device 140 may further determine a plurality of positions ofthe radiation source relative to the subject in the lateral direction,and/or in the vertical direction, such that the motion range of the ROIin the lateral direction, and/or the vertical direction may also becompletely covered by the radiation beams in each time bin. In someembodiments, by adjusting the position of the radiation source in thelateral direction and/or the vertical direction when the radiationsource emits the radiation beams, it may have the advantage of allowingimaging of the ROIs close to the edge of the transaxial FOV of theradiation beams.

In some embodiments, to perform the predictive scan, the processingdevice 140 may actively track the ROI and determine the plurality ofaxial positions for the radiation source according to varioustechniques. For example, the processing device 140 may detect motionvectors between cine images of the ROI. The processing device 140 mayfurther input the detected motion vectors to a predictor to predict themotion of the ROI. The predicted motion may include, for example, thepredicted axial positions of the ROI during a cycle of the physiologicalmotion. Then, in each time bin, the processing device 140 (e.g., theradiation beam emitting module 440) may cause the radiation source toemit, at multiple axial positions relative to the subject, radiationbeams to completely cover the ROI at the corresponding predicted axialposition to generate image frames of the ROI. In some embodiments, if asubject is instructed to hold his/her breath at a certain level ofinhalation or exhalation during the imaging of the ROI, the operation ofactively tracking the ROI may be omitted since the motion of the ROIassociated with the held breath of the subject may be ignored.

As another example, an implanted radio frequency (RF) beacon (e.g., usedin a Calypso system) may be used by way of surgical procedures to trackthe ROI. As still another example, an integrated magnetic resonance (MR)system may be used to present the real-time visualization of the ROI. Asstill another example, a radiation therapy system that has an attachedkilovoltage (kV) imaging system and/or a megavoltage (MV) imaging systemmay be used to perform pretreatment cine imaging of the ROI to provideposition information of the ROI.

FIG. 6 is a flowchart illustrating an exemplary process 600 fordetermining a motion range of the ROI according to some embodiments ofthe present disclosure. In some embodiments, at least part of theprocess 600 may be performed by the processing device 140 (implementedin, for example, the computing device 200 shown in FIG. 2). For example,the process 600 may be stored in a storage device (e.g., the storagedevice 150, the storage 220, the storage 390) in the form ofinstructions (e.g., an application), and invoked and/or executed by theprocessing device 140 (e.g., the processor 210 illustrated in FIG. 2,the CPU 340 illustrated in FIG. 3, or one or more modules in theprocessing device 140 illustrated in FIG. 4). The operations of theillustrated process presented below are intended to be illustrative. Insome embodiments, the process 600 may be accomplished with one or moreadditional operations not described, and/or without one or more of theoperations discussed. Additionally, the order of the operations of theprocess 600 as illustrated in FIG. 6 and described below is not intendedto be limiting. In some embodiments, the operation 502 may be achievedaccording to the process 600.

In 602, the processing device 140 (e.g., the motion range determinationmodule 410) may obtain an image of the subject based on a scan of thesubject.

In some embodiments, processing device 140 (e.g., the motion rangedetermination module 410) may obtain the image of the subject byperforming a scout scan of the subject using the imaging device 110. Forexample, in any one of a CT imaging system, a PET-CT imaging system, anda CT-linac system, the processing device 140 may move the subject to aCT imaging position to perform the scout scan.

In some embodiments, the obtained image may be a single image frame. Forexample, the obtained image may include a 3D CT image. The single imageframe may indicate the motion state of the subject (e.g., the positionof an ROI in the subject, the size of the ROI in the subject, the shapeof the ROI in the subject) at a specific time point.

In some embodiments, the obtained image may include multiple imageframes. For example, the obtained image may include cine images, a 4D CTimage, or the like, or any combination thereof. Specifically, themultiple image frames may indicate the varying motion state of thesubject (e.g., the position of an ROI in the subject, the size of theROI in the subject, the shape of the ROI in the subject) during at leastone full cycle of the physiological motion of the subject. In someembodiments, the multiple image frames may be correlated with thephysiological motion of the subject. For example, the multiple imageframes and a respiration motion signal representing the physiologicalmotion of the subject may be referenced to a common timebase for furtherprocessing. More descriptions regarding the respiration motion signalmay be found elsewhere in the present disclosure. See, e.g., FIG. 7 andrelevant descriptions thereof.

In 604, the processing device 140 (e.g., the motion range determinationmodule 410) may identify the ROI in the image of the subject.

In some embodiments, exemplary techniques for identifying the ROI ineach image frame may include an image segmentation technique, a manualannotation technique, a machine learning technique, or the like, or anycombination thereof. In some embodiments, the image segmentationtechnique may include a threshold-based segmentation technique, aregion-based segmentation technique, an edge-based segmentationtechnique, a segmentation technique based on specific theories, asegmentation technique based on genetic algorithms, a segmentationtechnique based on wavelet transforms, a segmentation technique based onclustering analysis, a segmentation technique based on mathematicalmorphology, a segmentation technique based on artificial neuralnetworks, or the like, or any combination thereof. In some embodiments,the manual annotation technique may include a manual annotationtechnique and a semi-manual annotation technique. For example, in amanual annotation technique, an operator may annotate an image based onthe digital imaging and communications in medicine (DICOM). In someembodiments, in a machine learning technique, a trained machine learningmodel may be used to identify the ROI in the image of the subject. Forexample, images with labeled ROIs may be used as training samples fortraining the machine learning model. Then the trained machine learningmodel may be used to identify one or more ROIs in an input image of thesubject.

In some embodiments, in the case that the obtained image includesmultiple image frames, the processing device 140 may identify the ROI indifferent image frames such that the motion states of the ROI atdifferent time points may be acquired.

In 606, the processing device 140 (e.g., the motion range determinationmodule 410) may determine the motion range of the ROI based on theidentified ROI.

In some embodiments, the processing device 140 (e.g., the motion rangedetermination module 410) may determine the motion range of the ROI in acoordinate system. The motion range of the ROI may be represented usingone or more set of coordinates in the coordinate system. For example,the motion range of the ROI in the axial direction may be delimited bytwo axial coordinates. For brevity, the two axial coordinates may bedescribed as a superior axial coordinate and an inferior axialcoordinate.

In the case that the obtained image includes multiple image frames, theprocessing device 140 (e.g., the motion range determination module 410)may determine the axial position of the ROI in each of the multipleimage frames. Then, the processing device 140 (e.g., the motion rangedetermination module 410) may determine the superior axial coordinateand the inferior axial coordinate of the motion range of the ROI on thebasis that all the axial positions of the ROI are always within therange delimited by the superior axial coordinate and the inferior axialcoordinate.

In the case that the obtained image is a single image frame, theprocessing device 140 (e.g., the motion range determination module 410)may determine the axial position of the ROI in the single image frame,and estimate the motion range of the ROI by, for example, extending therange of the axial position of the ROI in the single image frame.

It should be noted that the above descriptions of the process 600 areprovided for the purposes of illustration, and not intended to limit thescope of the present disclosure. For persons having ordinary skills inthe art, various modifications and changes in the forms and details ofthe application of the above method and system may occur withoutdeparting from the principles of the present disclosure. In someembodiments, the process 600 may include one or more other operations.However, those variations and modifications also fall within the scopeof the present disclosure.

FIG. 7 is a flowchart illustrating an exemplary process 700 for dividinga time-varying motion signal according to some embodiments of thepresent disclosure. In some embodiments, at least part of the process700 may be performed by the processing device 140 (implemented in, forexample, the computing device 200 shown in FIG. 2). For example, theprocess 700 may be stored in a storage device (e.g., the storage device150, the storage 220, the storage 390) in the form of instructions(e.g., an application), and invoked and/or executed by the processingdevice 140 (e.g., the processor 210 illustrated in FIG. 2, the CPU 340illustrated in FIG. 3, or one or more modules in the processing device140 illustrated in FIG. 4). The operations of the illustrated processpresented below are intended to be illustrative. In some embodiments,the process 700 may be accomplished with one or more additionaloperations not described, and/or without one or more of the operationsdiscussed. Additionally, the order of the operations of the process 700as illustrated in FIG. 7 and described below is not intended to belimiting. In some embodiments, the operation 504 may be achievedaccording to the process 700.

In 702, the processing device 140 (e.g., the physiological motiondividing module 420) may obtain a time-varying motion signalrepresenting the physiological motion via a sensor coupled to thesubject.

The sensor may collect time-varying information relating to, forexample, the respiration motion, the cardiac motion, etc., of thesubject. The processing device 140 may further analyze the time-varyinginformation to obtain the time varying motion signal including, forexample, a respiration motion signal, a cardiac motion signal, etc.

In some embodiments, the sensor may be included in a motion monitoringsystem for monitoring the physiological motion of the subject. Anexemplary motion monitoring system may include a respiration monitoringsystem, a cardiac monitoring system, or the like, or a combinationthereof. Specifically, the sensor may include a motion detection device,such as a camera (e.g., an infrared camera), a belt secured around thechest of the subject, or another pressure measurement technique ordevice to measure the change of pressure during the breathing cycles ofthe subject.

In some embodiments, the sensor may detect the motion of the subjectthroughout the imaging procedure described in the present disclosure.The time-varying motion signal may be correlated with one or more imagesof the subject. In some embodiments, the one or more images may includecine images, or a 4D CT image of the subject. The correlation betweenthe one or more images of the subject and the time-varying motion signalis achieved such that each single image frame in the one or more imagesis corresponding to a specific portion of the time-varying motionsignal. In a further embodiment, the processing device 140 may establisha relationship between the time-varying motion signal and the axialpositions of the ROI included in the one or more images.

In 704, the processing device 140 (e.g., the physiological motiondividing module 420) may divide the time-varying motion signal into aplurality of segments.

For illustration purpose, the time-varying motion signal represented bya time-varying motion waveform is taken as an example. The processingdevice 140 (e.g., the physiological motion dividing module 420) maydivide the time-varying motion waveform into a plurality of segments. Insome embodiments, the processing device 140 may divide the time-varyingmotion waveform according to an instruction from an operator (e.g., atechnician, a doctor). For example, as instructed by the operator, theprocessing device 140 may evenly divide the time-varying motion waveforminto segments such that the time bin corresponding to each segment hasan identical time span. As another example, as instructed by theoperator, the processing device 140 may unevenly divide the time-varyingmotion waveform into segments such that at least two segments may havedifferent time spans. In some embodiments, the processing device 140 maydivide the time-varying motion waveform into a plurality of segmentsusing a segmenting model. Merely by way of example, the segmenting modelmay perform the segmentation according to the distribution of thewaveform. For example, a segment at a sharply varying portion of thewaveform may be assigned with a smaller time span, and a segment at aslowly varying portion of the waveform may be assigned with a largertime span. In some embodiments, one or more time-varying motion signalsamples may be input to the segmenting model, with a plurality oflabeled segments, to train a preliminary segmenting model. When acertain condition is satisfied (e.g., a preset iteration count of thetraining process is met), the trained preliminary segmenting model maybe used as the segment model as described above.

It should be noted that the above descriptions of the process 700 areprovided for the purposes of illustration, and not intended to limit thescope of the present disclosure. For persons having ordinary skills inthe art, various modifications and changes in the forms and details ofthe application of the above method and system may occur withoutdeparting from the principles of the present disclosure. In someembodiments, other techniques, rather than using a sensor, may be usedto obtain the time-varying motion signal. For example, the time-varyingmotion signal may be derived from one or more images (e.g., cine images)of the subject by performing a scan on the subject in at least one fullcycle of the physiological motion of the subject. The processing device140 (e.g., the physiological motion dividing module 420) may extract thetime-varying motion signal directly from the one or more imagesaccording to, for example, the motion states of the subject in the oneor more images. In some embodiments, the process 700 may include one ormore other operations. However, those variations and modifications alsofall within the scope of the present disclosure.

FIG. 8 is a flowchart illustrating an exemplary process 800 fordetermining a plurality of axial positions for a radiation sourceaccording to some embodiments of the present disclosure. In someembodiments, at least part of the process 800 may be performed by theprocessing device 140 (implemented in, for example, the computing device200 shown in FIG. 2). For example, the process 800 may be stored in astorage device (e.g., the storage device 150, the storage 220, thestorage 390) in the form of instructions (e.g., an application), andinvoked and/or executed by the processing device 140 (e.g., theprocessor 210 illustrated in FIG. 2, the CPU 340 illustrated in FIG. 3,or one or more modules in the processing device 140 illustrated in FIG.4). The operations of the illustrated process presented below areintended to be illustrative. In some embodiments, the process 800 may beaccomplished with one or more additional operations not described,and/or without one or more of the operations discussed. Additionally,the order of the operations of the process 800 as illustrated in FIG. 7and described below is not intended to be limiting. In some embodiments,the operation 506 may be achieved according to the process 800.

In 802, the processing device 140 (e.g., e.g., the axial positiondetermination module 430) may determine an axial coverage of theradiation beams emitted from the radiation source.

The axial coverage of the radiation beams may denote the spatial rangeof the radiation beams along an axis that is extending along the axialdirection and traverses the isocenter of the imaging device 110. In someembodiments, the axial coverage of the radiation beams may also bereferred to as the axial FOV of the radiation beams.

In 804, the processing device 140 (e.g., the axial positiondetermination module 430) may determine the plurality of axial positionsfor the radiation source such that the motion range of the ROI in theaxial direction is within a combination of the axial coverages of theradiation source at the plurality of axial positions relative to thesubject.

In some embodiments, the processing device 140 (e.g., the axial positiondetermination module 430) may determine the plurality of axial positionsfor the radiation source based on the motion range of the ROI in theaxial direction and the axial coverage of the radiation beams emittedfrom the radiation source. For example, the processing device 140 (e.g.,the axial position determination module 430) may determine a pluralityof simulated axial positions, and determine a simulated combination ofthe axial coverages of the radiation beams emitted from the radiationsource at the plurality of simulated axial positions relative to thesubject. Then the processing device 140 (e.g., the axial positiondetermination module 430) may compare the simulated combination of theaxial coverages with the motion range of the ROI in the axial direction.Furthermore, the processing device 140 (e.g., the axial positiondetermination module 430) may adjust the plurality of simulated axialpositions based on the comparison result to determine the plurality ofaxial positions for the radiation source.

In some embodiments, the plurality of axial positions of the radiationsource relative to the subject may vary in steps or continuously. Forexample, the plurality of axial positions relative to the subject maycontinuously change while the radiation source is emitting the radiationbeams during each time bin. As another example, the plurality of axialpositions relative to the subject may be discrete positions and theradiation source may emit the radiation beams only when it reaches thedesignated positions.

It should be noted that the above descriptions of the process 800 areprovided for the purposes of illustration, and not intended to limit thescope of the present disclosure. For persons having ordinary skills inthe art, various modifications and changes in the forms and details ofthe application of the above method and system may occur withoutdeparting from the principles of the present disclosure. For example,the motion range of the ROI in the axial direction may be replaced withthe real-time axial range of the ROI in the axial direction. With thephysiological motion, the real-time axial range of the ROI may changewith time. The processing device 140 (e.g., the axial positiondetermination module 430) may track the motion of the ROI in real time,and determine the plurality of axial positions relative to the subjectbased on the real-time axial range of the ROI. That is, the combinationof the axial coverages of the radiation source at the plurality of axialpositions relative to the subject may vary with time. In someembodiments, one or more operations described in the process 800 may beomitted.

FIG. 9 is a flowchart illustrating an exemplary process 900 for causingthe radiation source to emit radiation beams according to someembodiments of the present disclosure In some embodiments, at least partof the process 900 may be performed by the processing device 140(implemented in, for example, the computing device 200 shown in FIG. 2).For example, the process 900 may be stored in a storage device (e.g.,the storage device 150, the storage 220, the storage 390) in the form ofinstructions (e.g., an application), and invoked and/or executed by theprocessing device 140 (e.g., the processor 210 illustrated in FIG. 2,the CPU 340 illustrated in FIG. 3, or one or more modules in theprocessing device 140 illustrated in FIG. 4). The operations of theillustrated process presented below are intended to be illustrative. Insome embodiments, the process 900 may be accomplished with one or moreadditional operations not described, and/or without one or more of theoperations discussed. Additionally, the order of the operations of theprocess 900 as illustrated in FIG. 9 and described below is not intendedto be limiting. In some embodiments, the operation 508 may be achievedaccording to the process 900.

In some embodiments, the subject may be supported by a table (e.g., thetable 114 of the imaging device 110) that is movable in the axialdirection. For example, in any one of a CT imaging, a PET-CT imagingsystem, and a CT-linac system, a table supporting the subject may bemovable in the axial direction.

In 902, the processing device 140 (e.g., the radiation beam emittingmodule 440) may cause the table to move to a table location such thatthe radiation source is at one of the plurality of axial positionsrelative to the subject.

In some embodiments, the plurality of axial positions may be representedusing one or more sets of coordinates. For example, the processingdevice 140 (e.g., the axial position determination module 430) mayestablish a coordinate system with the origin at, for example, theisocenter of the imaging device 110, the position of the radiationsource (or a position on the gantry 113 of the imaging device 110). Andthe processing device 140 (e.g., the radiation beam emitting module 440)may cause the table to move to a table location based on the pluralityof axial positions represented using the one or more sets ofcoordinates. In some embodiments, during each time bin as described inthe present disclosure, the processing device 140 may cause the table tomove to different table locations such that the radiation beams maycompletely cover the motion range (or the real-time axial range) of theROI in the time bin.

In 904, the processing device 140 (e.g., the radiation beam emittingmodule 440) may cause the radiation source to emit the radiation beamsto the ROI while the table is at the table location.

In some embodiments, the radiation source may generate X-rays with atleast two different energy spectra. In a dual energy CT system with asingle radiation source (e.g., the scanning source 115), an X-ray tubeincluded in the single radiation source may generate X-rays with a powersupply provided by a voltage generator. The power supply provided by thevoltage generator may rapidly switch between a low and a high X-ray tubevoltages, and then X-rays with two different energy spectra may begenerated to perform a scan on the ROI. Alternatively or additionally,the single radiation source may have two or more focal spots on theanode such that the single radiation source may emit the radiation beamsin different viewing angles. Alternatively, the single radiation sourcemay be replaced with multiple radiation sources. Each of the multipleradiation source may emit X-rays in different viewing angles, with sameor different energy spectra. Alternatively, a multilayer detector, whereeach detector layer exhibits a different energy response, may be used toachieve additional energy-spectrum-based contrast.

It should be noted that the above descriptions of the process 900 areprovided for the purposes of illustration, and not intended to limit thescope of the present disclosure. For persons having ordinary skills inthe art, various modifications and changes in the forms and details ofthe application of the above method and system may occur withoutdeparting from the principles of the present disclosure. In someembodiments, the process 900 may include one or more other operations.However, those variations and modifications also fall within the scopeof the present disclosure.

FIG. 10 is a flowchart illustrating an exemplary process 1000 forcausing the radiation source to emit radiation beams according to someembodiments of the present disclosure In some embodiments, at least partof the process 1000 may be performed by the processing device 140(implemented in, for example, the computing device 200 shown in FIG. 2).For example, the process 1000 may be stored in a storage device (e.g.,the storage device 150, the storage 220, the storage 390) in the form ofinstructions (e.g., an application), and invoked and/or executed by theprocessing device 140 (e.g., the processor 210 illustrated in FIG. 2,the CPU 340 illustrated in FIG. 3, or one or more modules in theprocessing device 140 illustrated in FIG. 4). The operations of theillustrated process presented below are intended to be illustrative. Insome embodiments, the process 1000 may be accomplished with one or moreadditional operations not described, and/or without one or more of theoperations discussed. Additionally, the order of the operations of theprocess 1000 as illustrated in FIG. 10 and described below is notintended to be limiting. In some embodiments, the operation 508 may beachieved according to the process 1000.

In some embodiments, the radiation source may be installed on a gantry(e.g., the gantry 113 of the imaging device 110) that is movable in theaxial direction. For example, in a CT-on-rails type system, a gantry maybe movable in the axial direction.

In 1002, the processing device 140 (e.g., the radiation beam emittingmodule 440) may cause the gantry to move to a gantry location such thatthe radiation source is at one of the plurality of axial positionsrelative to the subject.

In some embodiments, the plurality of axial positions may be representedusing one or more sets of coordinates. For example, the processingdevice 140 (e.g., the axial position determination module 430) mayestablish a coordinate system with the origin at, for example, theisocenter of the imaging device 110, a position on the table (e.g., aposition on the table 114 of the imaging device 110). And the processingdevice 140 (e.g., the radiation beam emitting module 440) may cause thegantry to move to a gantry location based on the plurality of axialpositions represented using the one or more sets of coordinates. In someembodiments, during each time bin as described in the presentdisclosure, the processing device 140 may cause the gantry to move todifferent gantry locations such that the radiation beams may completelycover the motion range (or the real-time axial range) of the ROI in thetime bin.

In 1004, the processing device 140 (e.g., the radiation beam emittingmodule 440) may cause the radiation source to emit the radiation beamsto the ROI while the gantry is at the gantry location. More descriptionsregarding the emitting of the radiation beams may be found elsewhere inthe present disclosure. See, e.g., FIG. 9 and the descriptions thereof.

It should be noted that the above descriptions of the process 1000 areprovided for the purposes of illustration, and not intended to limit thescope of the present disclosure. For persons having ordinary skills inthe art, various modifications and changes in the forms and details ofthe application of the above method and system may occur withoutdeparting from the principles of the present disclosure. In someembodiments, the process 1000 may include one or more other operations.However, those variations and modifications also fall within the scopeof the present disclosure.

FIG. 11 is a flowchart illustrating an exemplary process 1100 fordetermining at least one time bin according to some embodiments of thepresent disclosure In some embodiments, at least part of the process1100 may be performed by the processing device 140 (implemented in, forexample, the computing device 200 shown in FIG. 2). For example, theprocess 1100 may be stored in a storage device (e.g., the storage device150, the storage 220, the storage 390) in the form of instructions(e.g., an application), and invoked and/or executed by the processingdevice 140 (e.g., the processor 210 illustrated in FIG. 2, the CPU 340illustrated in FIG. 3, or one or more modules in the processing device140 illustrated in FIG. 4). The operations of the illustrated processpresented below are intended to be illustrative. In some embodiments,the process 1100 may be accomplished with one or more additionaloperations not described, and/or without one or more of the operationsdiscussed. Additionally, the order of the operations of the process 1100as illustrated in FIG. 11 and described below is not intended to belimiting. In some embodiments, the operation 512 may be achievedaccording to the process 1100.

In 1102, the processing device 140 (e.g., the time bin determinationmodule 460) may obtain a planned position of the ROI at which thetherapeutic beams are to be emitted.

In some embodiments, the planned position of the ROI at which thetherapeutic beams are to be emitted may be set in a predeterminedtreatment plan. For example, an operator may determine the plannedposition of the ROI at which the therapeutic beams are to be emittedbased on a previous CT scan. In some embodiments, the planned positionof the ROI may include a position of the ROI relative to otherorgans/tissues in the subject, a position of the ROI relative to theradiation source that emits the therapeutic beams, a position of the ROIrelative to other components of the imaging device 110 (e.g., the gantry113), or the like, or a combination thereof. Information (e.g., one ormore set of coordinates) related to the planned position may be storedin a storage device (e.g., the storage device 150, the storage 220, thestorage 390). The processing device 140 (e.g., the time bindetermination module 460) may obtain the planned position of the ROI atwhich the therapeutic beams are to be emitted from storage device.

In 1104, the processing device 140 (e.g., the time bin determinationmodule 460) may determine, among the positions of the ROI in the axialdirection, at least one position of the ROI that matches the plannedposition of the ROI at which the therapeutic beams are to be emitted.

In some embodiments, the positions of the ROI in the axial direction maybe determined as described elsewhere in the disclosure (e.g., theoperation 510). For example, the processing device 140 may determine thepositions of the ROI in the axial direction by identifying the ROI inthe image frames generated according to the “exhaustive scan” or the“predictive scan” in each time bin.

In some embodiments, the position of the ROI in the axial directionmatches the planned position of the ROI may denote that the axialposition of the ROI relative to another organ/tissue in the subject maybe same as the planned axial position of the ROI relative to the sameorgan/tissue in the subject. In some embodiments, the processing device140 (e.g., the time bin determination module 460) may obtain an image ofthe ROI at the planned position (e.g., the plan image), and compare itwith image frames corresponding to different time bins and differentpositions of the ROI in the axial direction. If the image of the ROI atthe planned position coincides with a specific image frame (e.g., thepositions of the ROI in two images coincides with each other), theprocessing device 140 (e.g., the time bin determination module 460) maydetermine the position of the ROI in the specific image frame as one ofthe at least one position of the ROI that matches the planned positionof the ROI at which the therapeutic beams are to be emitted.

In 1106, the processing device 140 (e.g., the time bin determinationmodule 460) may determine the at least one time bin based on the atleast one matched position of the ROI.

As described elsewhere in the present disclosure, for each of theplurality time bins in a full cycle of the physiological motion, aposition of the ROI in the axial direction may be determined.Additionally, the relationship between the positions of the ROI in theaxial direction and the physiological motion (e.g., represented by atime-varying motion signal) may be established. The processing device140 may determine the at least one time bin corresponding to the atleast one matched position of the ROI based on the relationship.

In some embodiments, after the at least one time bin is determined, theprocessing device 140 may cause the imaging device 110 (e.g., the table114) to move the subject to the treatment position, and the therapeuticbeams may be emitted for the planned position of the ROI within timeintervals corresponding to the at least one time bin. As used herein, ifa time interval and the at least one time bin correspond to a same phaseof the physiological motion (e.g., the respiration motion, the cardiacmotion), the time interval may be deemed as corresponding to the atleast one time bin.

It should be noted that the above descriptions of the process 1100 areprovided for the purposes of illustration, and not intended to limit thescope of the present disclosure. For persons having ordinary skills inthe art, various modifications and changes in the forms and details ofthe application of the above method and system may occur withoutdeparting from the principles of the present disclosure. In someembodiments, the process 1100 may include one or more other operations.However, those variations and modifications also fall within the scopeof the present disclosure. For example, the operations illustrated inthe process 1100 may be applied in other applications including, forexample, surgical interventions, and treatments such as a high intensityfocused ultrasound (HIFU), a hyperthermia therapy, a brachytherapy, acryotherapy, or the like, or any combination thereof.

In the scope of application of the above descriptions to therapy withbeams originating external to the patient, it will be recognized thattherapeutic beams may enter the patient from one or more angles, or overone or more continuous angular ranges. It will furthermore be recognizedthat by imaging a ROI, which has a component of motion in the axialdirection, from the angles at which the external therapy beams willenter the patient, that the motion trajectory of the ROI may be mostrelevantly determined from the point-of-view corresponding to the beamangle(s)/beam angular range(s) of the planned therapeutic beam entry(beam's-eye-view imaging). Such therapeutic beams may include x-raybeams, charged particle beams, neutron beams, ultrasound beams, etc.

Having thus described the basic concepts, it may be rather apparent tothose skilled in the art after reading this detailed disclosure that theforegoing detailed disclosure is intended to be presented by way ofexample only and is not limiting. Various alterations, improvements, andmodifications may occur and are intended to those skilled in the art,though not expressly stated herein. These alterations, improvements, andmodifications are intended to be suggested by this disclosure, and arewithin the spirit and scope of the exemplary embodiments of thisdisclosure.

Moreover, certain terminology has been used to describe embodiments ofthe present disclosure. For example, the terms “one embodiment,” “anembodiment,” and/or “some embodiments” mean that a particular feature,structure or characteristic described in connection with the embodimentis included in at least one embodiment of the present disclosure.Therefore, it is emphasized and should be appreciated that two or morereferences to “an embodiment” or “one embodiment” or “an alternativeembodiment” in various portions of this specification are notnecessarily all referring to the same embodiment. Furthermore, theparticular features, structures or characteristics may be combined assuitable in one or more embodiments of the present disclosure.

Further, it will be appreciated by one skilled in the art, aspects ofthe present disclosure may be illustrated and described herein in any ofa number of patentable classes or context including any new and usefulprocess, machine, manufacture, or composition of matter, or any new anduseful improvement thereof. Accordingly, aspects of the presentdisclosure may be implemented entirely hardware, entirely software(including firmware, resident software, micro-code, etc.) or combiningsoftware and hardware implementation that may all generally be referredto herein as a “unit,” “module,” or “system.” Furthermore, aspects ofthe present disclosure may take the form of a computer program productembodied in one or more computer readable media having computer readableprogram code embodied thereon.

A computer readable signal medium may include a propagated data signalwith computer readable program code embodied therein, for example, inbaseband or as part of a carrier wave. Such a propagated signal may takeany of a variety of forms, including electro-magnetic, optical, or thelike, or any suitable combination thereof. A computer readable signalmedium may be any computer readable medium that is not a computerreadable storage medium and that may communicate, propagate, ortransport a program for use by or in connection with an instructionexecution system, apparatus, or device. Program code embodied on acomputer readable signal medium may be transmitted using any appropriatemedium, including wireless, wireline, optical fiber cable, RF, or thelike, or any suitable combination of the foregoing.

Computer program code for carrying out operations for aspects of thepresent disclosure may be written in any combination of one or moreprogramming languages, including an object oriented programming languagesuch as Java, Scala, Smalltalk, Eiffel, JADE, Emerald, C++, C#, VB. NET,Python or the like, conventional procedural programming languages, suchas the “C” programming language, Visual Basic, Fortran 2103, Peri, COBOL2102, PHP, ABAP, dynamic programming languages such as Python, Ruby andGroovy, or other programming languages. The program code may executeentirely on the user's computer, partly on the user's computer, as astand-alone software package, partly on the user's computer and partlyon a remote computer or entirely on the remote computer or server. Inthe latter scenario, the remote computer may be connected to the user'scomputer through any type of network, including a local area network(LAN) or a wide area network (WAN), or the connection may be made to anexternal computer (for example, through the Internet using an InternetService Provider) or in a cloud computing environment or offered as aservice such as a Software as a Service (SaaS).

Furthermore, the recited order of processing elements or sequences, orthe use of numbers, letters, or other designations therefore, is notintended to limit the claimed processes and methods to any order exceptas may be specified in the claims. Although the above disclosurediscusses through various examples what is currently considered to be avariety of useful embodiments of the disclosure, it is to be understoodthat such detail is solely for that purpose, and that the appendedclaims are not limited to the disclosed embodiments, but, on thecontrary, are intended to cover modifications and equivalentarrangements that are within the spirit and scope of the disclosedembodiments. For example, although the implementation of variouscomponents described above may be embodied in a hardware device, it mayalso be implemented as a software only solution, for example, aninstallation on an existing server or mobile device.

Similarly, it should be appreciated that in the foregoing description ofembodiments of the present disclosure, various features are sometimesgrouped together in a single embodiment, figure, or description thereoffor the purpose of streamlining the disclosure aiding in theunderstanding of one or more of the various inventive embodiments. Thismethod of disclosure, however, is not to be interpreted as reflecting anintention that the claimed object matter requires more features than areexpressly recited in each claim. Rather, inventive embodiments lie inless than all features of a single foregoing disclosed embodiment.

In some embodiments, the numbers expressing quantities or propertiesused to describe and claim certain embodiments of the application are tobe understood as being modified in some instances by the term “about,”“approximate,” or “substantially.” For example, “about,” “approximate,”or “substantially” may indicate ±20% variation of the value itdescribes, unless otherwise stated. Accordingly, in some embodiments,the numerical parameters set forth in the written description andattached claims are approximations that may vary depending upon thedesired properties sought to be obtained by a particular embodiment. Insome embodiments, the numerical parameters should be construed in lightof the number of reported significant digits and by applying ordinaryrounding techniques. Notwithstanding that the numerical ranges andparameters setting forth the broad scope of some embodiments of theapplication are approximations, the numerical values set forth in thespecific examples are reported as precisely as practicable.

Each of the patents, patent applications, publications of patentapplications, and other material, such as articles, books,specifications, publications, documents, things, and/or the like,referenced herein is hereby incorporated herein by this reference in itsentirety for all purposes, excepting any prosecution file historyassociated with same, any of same that is inconsistent with or inconflict with the present document, or any of same that may have alimiting affect as to the broadest scope of the claims now or laterassociated with the present document. By way of example, should there beany inconsistency or conflict between the description, definition,and/or the use of a term associated with any of the incorporatedmaterial and that associated with the present document, the description,definition, and/or the use of the term in the present document shallprevail.

In closing, it is to be understood that the embodiments of theapplication disclosed herein are illustrative of the principles of theembodiments of the application. Other modifications that may be employedmay be within the scope of the application. Thus, by way of example, butnot of limitation, alternative configurations of the embodiments of theapplication may be utilized in accordance with the teachings herein.Accordingly, embodiments of the present application are not limited tothat precisely as shown and described.

What is claimed is:
 1. A method implemented on a computing device havingat least one storage device storing a set of instructions, and at leastone processor in communication with the at least one storage device, themethod comprising: determining a motion range of a region of interest(ROI) of a subject in an axial direction, wherein the ROI moves due to aphysiological motion of the subject; dividing the physiological motioninto a plurality of time bins; in at least one of the plurality of timebins, determining, for a radiation source, a plurality of axialpositions relative to the subject; and causing the radiation source toemit, at each of the plurality of axial positions relative to thesubject, radiation beams to the ROI to generate an image frame of theROI, wherein the radiation beams corresponding to the plurality of axialpositions jointly cover the motion range of the ROI in the axialdirection; and determining, for each of the plurality of time bins, aposition of the ROI in the axial direction based on the image frames ofthe ROI generated in the corresponding time bin; and determining, basedon the positions of the ROI in the axial directions and among theplurality of time bins, at least one time bin in which therapeutic beamsare to be emitted to the ROI.
 2. The method of claim 1, wherein thedetermining a motion range of an ROI of a subject in an axial directioncomprises: obtaining an image of the subject based on a scan of thesubject; identifying the ROI in the image of the subject; anddetermining the motion range of the ROI based on the identified ROI. 3.The method of claim 1, wherein the physiological motion of the subjectincludes at least one of a respiration motion or a cardiac motion of thesubject.
 4. The method of claim 1, wherein the radiation sourcegenerates X-rays with at least two different energy spectra.
 5. Themethod of claim 1, wherein the dividing the physiological motion into aplurality of time bins comprises: obtaining a time-varying motion signalrepresenting the physiological motion via a sensor coupled to thesubject; and dividing the time-varying motion signal into a plurality ofsegments, each of the plurality of the segments corresponding to one ofthe plurality of time bins.
 6. The method of claim 1, wherein thedetermining, for a radiation source, a plurality of axial positionsrelative to the subject comprises: determining an axial coverage of theradiation beams of the radiation source; and determining the pluralityof axial positions for the radiation source such that the motion rangeof the ROI in the axial direction is within a combination of the axialcoverages of the radiation source at the plurality of axial positionsrelative to the subject.
 7. The method of claim 1, wherein the subjectis supported by a table that is movable in the axial direction, whereinthe causing the radiation source to emit, at each of the plurality ofaxial positions relative to the subject, radiation beams to the ROI togenerate an image frame of the ROI comprises: causing the table to moveto a table location such that the radiation source is at one of theplurality of axial positions relative to the subject; and causing theradiation source to emit the radiation beams to the ROI while the tableis at the table location.
 8. The method of claim 1, wherein theradiation source is installed on a gantry that is movable in the axialdirection, wherein the causing the radiation source to emit, at each ofthe plurality of axial positions relative to the subject, radiationbeams to the ROI to generate an image frame of the ROI comprises:causing the gantry to move to a gantry location such that the radiationsource is at one of the plurality of axial positions relative to thesubject; and causing the radiation source to emit the radiation beams tothe ROI while the gantry is at the gantry location.
 9. The method ofclaim 1, wherein the determining, based on the positions of the ROI inthe axial directions and among the plurality of time bins, at least onetime bin, in which therapeutic beams are to be emitted to the ROIcomprises: obtaining a planned position of the ROI at which thetherapeutic beams are to be emitted; determining, among the positions ofthe ROI in the axial direction, at least one position of the ROI thatmatches the planned position of the ROI at which the therapeutic beamsare to be emitted; and determining the at least one time bin based onthe at least one matched position of the ROI.
 10. The method of claim 1,further comprising: tracking a motion of the ROI, wherein thedetermining, for a radiation source, a plurality of axial positionsrelative to the subject comprises: determining the plurality of axialpositions relative to the subject based on the tracked motion of theROI.
 11. The method of claim 1, wherein the causing the radiation sourceto emit, at each of the plurality of axial positions relative to thesubject, radiation beams to the ROI to generate an image frame of theROI comprises: causing the radiation source to emit, at each of theplurality of axial positions relative to the subject, radiation beams tothe ROI from one or more angles at which the therapeutic beams are to beemitted to the ROI.
 12. A system, comprising: at least one storagemedium including a set of instructions; and at least one processor incommunication with the at least one storage medium, wherein whenexecuting the instructions, the at least one processor is configured todirect the system to perform operations including: determining a motionrange of a region of interest (ROI) of a subject in an axial direction,wherein the ROI moves due to a physiological motion of the subject;dividing the physiological motion into a plurality of time bins; in atleast one of the plurality of time bins, determining, for a radiationsource, a plurality of axial positions relative to the subject; andcausing the radiation source to emit, at each of the plurality of axialpositions relative to the subject, radiation beams to the ROI togenerate an image frame of the ROI, wherein the radiation beamscorresponding to the plurality of axial positions jointly cover themotion range of the ROI in the axial direction; and determining, foreach of the plurality of time bins, a position of the ROI in the axialdirection based on the image frames of the ROI generated in thecorresponding time bin; and determining, based on the positions of theROI in the axial directions and among the plurality of time bins, atleast one time bin in which therapeutic beams are to be emitted to theROI.
 13. The system of claim 12, wherein the determining a motion rangeof an ROI of a subject in an axial direction comprises: obtaining animage of the subject based on a scan of the subject; identifying the ROIin the image of the subject; and determining the motion range of the ROIbased on the identified ROI.
 14. The system of claim 12, wherein thephysiological motion of the subject includes at least one of arespiration motion or a cardiac motion of the subject.
 15. The system ofclaim 12, wherein the radiation source generates X-rays with at leasttwo different energy spectra.
 16. The system of claim 12, wherein thedividing the physiological motion into a plurality of time binscomprises: obtaining a time-varying motion signal representing thephysiological motion via a sensor coupled to the subject; and dividingthe time-varying motion signal into a plurality of segments, each of theplurality of the segments corresponding to one of the plurality of timebins.
 17. The system of claim 12, wherein the determining, for aradiation source, a plurality of axial positions relative to the subjectcomprises: determining an axial coverage of the radiation beams of theradiation source; and determining the plurality of axial positions forthe radiation source such that the motion range of the ROI in the axialdirection is within a combination of the axial coverages of theradiation source at the plurality of axial positions relative to thesubject.
 18. The system of claim 12, wherein the determining, based onthe positions of the ROI in the axial directions and among the pluralityof time bins, at least one time bin, in which therapeutic beams are tobe emitted to the ROI comprises: obtaining a planned position of the ROIat which the therapeutic beams are to be emitted; determining, among thepositions of the ROI in the axial direction, at least one position ofthe ROI that matches the planned position of the ROI at which thetherapeutic beams are to be emitted; and determining the at least onetime bin based on the at least one matched position of the ROI.
 19. Thesystem of claim 12, further comprising: tracking a motion of the ROI,wherein the determining, for a radiation source, a plurality of axialpositions relative to the subject comprises: determining the pluralityof axial positions relative to the subject based on the tracked motionof the ROI.
 20. The system of claim 12, wherein the causing theradiation source to emit, at each of the plurality of axial positionsrelative to the subject, radiation beams to the ROI to generate an imageframe of the ROI comprises: causing the radiation source to emit, ateach of the plurality of axial positions relative to the subject,radiation beams to the ROI from one or more angles at which thetherapeutic beams are to be emitted to the ROI.